Confirmation: Our Sun is Normal

NASA/SDO
Our sun has provided a wonderful opportunity to study a star up close, but until recently, astrophysicists have only been able to extrapolate this single example to other stars in the universe. The Kepler space telescope, now in its K2 mission, is providing a new opportunity. Scientists at the Leibniz Institute for Astrophysics Potsdam and Johns Hopkins University used Kepler to closely study a cluster called M67 that contains stars the same age as our sun. They were able to determine, by watching how the sunspots move, that those four-billion-year-old stars spin every 28 days, just like our sun. This discovery lends more proof to the solar-stellar connection, that “our sun and other stars share similar dynamical properties,” — in this case, that the sun’s rotation is indeed related to its age. Jörn Weingrill, an astrophysicist with Leibniz who participated in the research, says, “The rotational evolution of a star is mainly driven by its stellar winds,” and as a star ages, the winds cause its rotation to slow. They can use this information to “trace back the evolution of our home star,” and find that at our sun’s birth, it rotated every 1.1 days. “Apart from this,” Weingrill says, “we can estimate the strength of the stellar winds and learn about the space environment that enclosed our planets in the past.”